package com.luck.pf.util;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;

import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.luck.pf.common.Constants;

public class DrawImage extends HttpServlet {
	private static final long serialVersionUID = 1L;

	public void destroy() {
		super.destroy(); // Just puts "destroy" string in log
		// Put your code here
	}

	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

		doPost(request, response);
	}

	 public void doPost(HttpServletRequest request, HttpServletResponse response)
     throws ServletException, IOException {
		 response.setHeader("Pragma","No-cache");
		 response.setHeader("Cache-Control","no-cache");
		 response.setDateHeader("Expires", 0);
		 int width=60, height=20;
		 BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);

		 // 获取图形上下文
		 Graphics g = image.getGraphics();

		 //生成随机类
		 Random random = new Random();

		 // 设定背景色
		 g.setColor(getRandColor(200,250));
		 g.fillRect(0, 0, width, height);

		 //设定字体
		 g.setFont(new Font("Times New Roman",Font.PLAIN,18));
		 g.setColor(getRandColor(160,200));
		 for (int i=0;i<155;i++)
		 {
		  int x = random.nextInt(width);
		  int y = random.nextInt(height);
		         int xl = random.nextInt(12);
		         int yl = random.nextInt(12);
		  g.drawLine(x,y,x+xl,y+yl);
		 }

		 // 取随机产生的认证码(4位数字)
		 String sRand="";
		 for (int i=0;i<4;i++){
		     String rand=String.valueOf(random.nextInt(10));
		     sRand+=rand;
		     // 将认证码显示到图象中
		     g.setColor(new Color(20+random.nextInt(110),20+random.nextInt(110),20+random.nextInt(110)));//调用函数出来的颜色相同，可能是因为种子太接近，所以只能直接生成
		     g.drawString(rand,13*i+6,16);
		 }

		 // 将认证码存入SESSION
		 request.getSession().setAttribute(Constants.SESSION_VALIDATE_CODE,sRand.toLowerCase());


		 // 图象生效
		 g.dispose();

		 // 输出图象到页面
		 ImageIO.write(image, "JPEG", response.getOutputStream());

	 }
	 Color getRandColor(int fc,int bc){//给定范围获得随机颜色
	        Random random = new Random();
	        if(fc>255) fc=255;
	        if(bc>255) bc=255;
	        int r=fc+random.nextInt(bc-fc);
	        int g=fc+random.nextInt(bc-fc);
	        int b=fc+random.nextInt(bc-fc);
	        return new Color(r,g,b);
	        }
}
